"Oblique cone" - pros and cons?

[graaf]

Hi to all!

take a look at this:
http://www.jvc-victor.co.jp/company/...one/index.html
http://www.jvc-victor.co.jp/audio_w/...l33/index.html

interesting, isn't it?
looks like something special... but who knows?

what do You think?

best!
graaf

[rdf]

Fiendishly clever. On first glance the surround would appear a nightmare to design. You'd expect the driver to rock towards the large end at high excursion.

[graaf]

the idea seems to be to make the soundwave reach the surround not simultaneously along all radiuses but at slightly different times due to uneven path lengths thanks to cone asymmetry

I wonder if the same effect could be achieved by applying a kind of asymmetrical pattern treatment to a paper cone making the sound wave travel slightly faster/slower along different radiuses?

[soongsc]

I've seen a few of these around here, but have not measured any. It seems dynamic mass and static forces all need to be taken into consideration. What would interest me is the radiation pattern/directivity.

[Cal Weldon]

What interests me is why you would consider offsetting the mass of the cone.

[soongsc]

I think if one looks at the data shown in the links of the first post, it is clear they want to eliminate the breakup mode. I'm not sure whether the intention as to use mass off-setting or not. The concept of shape off-set seems more adequate with domes rather than cones.

[454Casull]

I wonder if an elliptical diaphragm could achieve the same effect.

[Moondog55]

Not really a new idea, Yamaha did something very like this with their ear-shaped woofer way back.
Never get a chance to listen to that one every time they come up on E*** there is stiff competition and heavy bidding, so the question is " Does it work" ??

[rdf]

As I recall the 'ear speaker' was more a coil driven tensioned membrane without a true surround. The intent here seems to distribute the cone face's standing waves in frequency. Either it's advances in finite element modeling ushering a new paradigm in speakers or another short lived marketing fad that leaves no residue, like 'ear speakers'.

[Iain McNeill]

Originally posted by Cal Weldon
What interests me is why you would consider offsetting the mass of the cone.

Hi Cal!
It's the alternative solution to making the damped, spring-loaded mass intrinsically perfect. Instead, you embrace and nurture the resonances. You want an infinite number of them so that the response becomes flat because every frequency is equally resonant. I think the key phrase is "..in the limit..."

NXT has a technology that uses this principal too. They have a piezzo (I believe) transducer that you can slap on any old plastic surface to make a speaker. The trick is finding the stimulation point that enables the greatest number of nodes.

Statistically, it's fantastic